Work crews lay down special mats Saturday to protect the lawn on the National Mall in Washington, D.C., in preparation for the 57th presidential inauguration.

WASHINGTON — Tens of thousands of visitors — most, but not all, happy Democrats — streamed into a dressed-up capital city this weekend as organizers prepared for an inauguration that, while not as grand as four years ago, is still cause for celebration supporters of President Barack Obama.

Barbara and Loren Ing drove their minivan here from rural Ohio, lugging a trailer filled with glass centerpieces. As a volunteer for the society representing her native state, Illinois, Barbara Ing — who ordinarily works in the layaway department of her local Kmart — spent months creating the table decor for the society’s inaugural ball, one of countless unofficial parties marking Obama’s second swearing-in.

At the historic Willard Hotel — where the four-night inaugural rate for elegant “Oval Suites” is $22,800, with a $27,000 catering minimum — women in mink coats and pearls milled about the lobby.

The bartender mixed “Blue Hawaiians” in honor of Obama’s birthplace. In the kitchen, the pastry chef spent last week baking delicate French macarons in red, white and blue.

By Saturday afternoon, out-of-towners clutching maps strolled past the White House in the bright sunshine, as street vendors hawked inaugural trinkets. Parade reviewing stands were decked with patriotic bunting, Pennsylvania Avenue was lined with flags, and across town at the Washington Convention Center, workers were busy erecting lighting and stages for Obama’s two official inaugural balls.

Tens of thousands of ticketholders will cram into the 2.3-million-square-foot convention center on Monday night to hear Smokey Robinson, Stevie Wonder, Alicia Keys and the cast of TV’s “Glee” — all while hoping for a glimpse of Obama and his wife, Michelle, twirling around the dance floor.

“It’s clearly not as big or as plentiful or elaborate as the last time, but in many ways for Democrats it’s even sweeter,” said Hilary Rosen, a prominent Obama supporter. “People are thrilled about the president; there are a record number of women in the Senate. Gay people are happy, and Latinos. You have these pillars of the election; it meant something different to everybody, but it culminated in this collectively powerful feeling.”

For Donna Hardy, a federal employee from Oakland, Calif., who walked in front of the White House on Saturday clutching a newly purchased “Obama” hat, the second swearing-in is more historic than the first.

‘’An African American being elected back to back?” she asked. “I don’t think we’ll ever see that again.”

Officials expect 600,000 to 800,000 people to turn out on the National Mall to witness Monday’s ceremony on the West Front of the Capitol — a crowd typical for most inaugurations but far short of the 1.8 million who clogged the city in 2009, creating pedestrian gridlock that kept many attendees from getting to their seats.

This year, the congressional committee overseeing the Capitol ceremony arranged for extra cellphone towers on the Mall, and devised a mobile phone app with a GPS system to help inaugural-goers navigate the city, said Sen. Charles E. Schumer, D-N.Y., the committee chairman.

Schumer spent Saturday at the Capitol, overseeing preparations as tables were set in Statuary Hall for Monday’s inaugural luncheon. As master of ceremonies, he will make opening remarks and introduce the participants; he said the thought that “so many people who have been waiting with anticipation for months won’t be able to get their seats” was one of two fears that had kept him awake at night. The other is that he will miss his cue to introduce the chief justice.

“I’m practicing my speech, but I’m less worried about that and more worried about when I’m supposed to get up and say, ‘Ladies and gentlemen, Mr. John Roberts Jr., the chief justice of the Supreme Court,” he said. “I’m worried I won’t get up in time.”

Obama will take his official oath on Sunday just before noon in the Blue Room of the White House; the Constitution states that presidential terms expire at noon on Jan. 20. Monday’s festivities, which coincide with Martin Luther King’s Birthday, are ceremonial. (Obama will use one of King’s Bibles, along with one that belonged to Abraham Lincoln, when he retakes the oath on Monday.)

To honor King, Obama designated Saturday a national day of service. He and Michelle, and their daughters, Malia and Sasha, spent part of the afternoon helping to refurbish an elementary school in Northeast Washington, with hundreds of other volunteers organized by the City Year nonprofit group. Barack and Michelle Obama stained a bookshelf.

While much of Washington is gearing up for a party, some Republicans are lying low — or getting out of town.

“My wife had a partial knee replacement, so I am staying with her in Mississippi,” Trent Lott, the former senator from that state, wrote in an email. “Most Republicans will be otherwise busy. Some will attend events and parties, because it does only happen every four years.”

But Democrats are in the mood to celebrate. Emily’s List, which helps elect Democratic women who favor abortion rights, was planning a party for 1,400 to welcome female congressional newcomers, including Sens. Elizabeth Warren of Massachusetts and Tammy Baldwin of Wisconsin.

“We’re celebrating our shattering of glass ceilings everywhere,” said Jen Bluestein, the group’s communications director. The Futuro Fund, which mobilized Hispanic voters in support of Obama, staged a symposium on Latino issues on Saturday as part of a three-day “Latino Inaugural.” The group was planning a star-studded celebration at the Kennedy Center on Sunday night, headlined by Eva Longoria, the “Desperate Housewives” actress, Jose Feliciano, Chita Rivera, Rita Moreno and other Hispanic entertainers.

Although Bruce Springsteen — a staple of Obama campaign events — will not be returning to Washington for this year’s inauguration, James Taylor will perform “America the Beautiful,” Kelly Clarkson will sing “My Country ‘Tis of Thee,” and Beyonce will close the inaugural ceremony with the national anthem.

In 2009, hotels were sold out months in advance; marketing representatives said rooms were finally booking up last week, in part because celebrities and their entourages were making last-minute decisions to come.

“The amount of celebrities, the wattage, may be a little dimmer,” said Barbara Martin, whose business, BrandLinkDC, represents luxury clients, including the W Hotel on the Pennsylvania Avenue parade route. “Like, I don’t think Beyonce is party-hopping. That being said, I feel that there are just as many A-list and B-list celebrities. There are probably fewer A-plus ones.”

This being Washington, all sorts of companies, organizations and federal agencies are trying to get in on the act. Knob Creek, the Kentucky bourbon maker, is promoting itself as “the exclusive whiskey being served” at a candlelight celebration Obama is hosting for his donors at the National Building Museum on Sunday night.

The U.S. Geological Survey is hoping reporters will write about the building material used to construct both the Capitol and the White House: Aquia Creek sandstone. The National Archives, in a rare treat for history buffs, is marking the inauguration by putting two pages of George Washington’s first inaugural address — a document ordinarily in a vault — on display.

“It’s one of those documents that I informally call a goose bump — it gives me goose bumps,” said Michael Hussey, the curator of the exhibit, which closes at the end of the month.

Though some view the inauguration as partisan, Steve Kerrigan, chairman of Obama’s inaugural committee, said he and his staff hoped that Americans would “walk away from this with the sense that it is not just a celebration of the president, but a celebration of the entire country.”

That is the view of Barbara Ing, the volunteer from Ohio. She voted for Mitt Romney, Obama’s Republican opponent. This is her fifth inaugural making the centerpieces for the Illinois ball.

‘’Every inaugural seems different,” she said. “Different energy, different people. I think everybody should do it at least once.”